Circuit-breaker



(No Model.)

H. LEMP. CIRCUIT BREAK-ER.

R Patented Aug. 10,1897.

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UNITED STATES PATENT ()FFIcE.

I'IERMANN LEMP, OF LYNN, MASSACHUSETTS, ASSIGNOR TO THE GENERAL ELECTRIC COMPANY, OF NEIV YORK.

CIRCUIT-BREAKER.

SPECIFICATION forming part of Letters Patent No. 587,838, dated August 10, 1897.

Application filed April 3, 1897. Serial No. 680,546. (No model.)

To all whom, it may concern.-

Be it known that I, HERMANN LEMP, a citizen of the United States, residing at Lynn, in the county of Essex, State of Massachusetts, have invented certain new and useful Improvements in Circuit-Breakers, (Case No. 518,) of which the following is a specification.

My invention relates to circuit-breakers, or, as they are sometimes called, contact- I o breakers, and especially to an improved form of contact breaker suitable for use with Ruhmkorff coils.

To obtain the maximum work from a Ruhmkorff coil it is necessary to allow ample time for the energizing or magnetizing current to m agnetize the iron core of the coil and then to very suddenly disrupt the charging-current. The eifect of this is to largely overcome the self-induction of the coil, which with the ordinary makc-andbreak arrangement or rheotome tends to limit the charging-current and prevents the iron core reaching its highest state of magnetization. In the present construction the time during which the coil is receiving current and the iron core being magnetized is much longer than the period of cessation of current in the primary circuit, and is thus longer than the time of discharge of the magnetism of the core acting on the fine Wire or secondary circuit. It is found that by this mode of working, using a suitable make-and-break arrangement and a snit able condenser, the output of energy in the secondary circuit is greatly increased.

The greatest difficulty to be overcome in make-and-break contact appliances for use in connection with Ruhmkorff or induction coils has been in the contacts themselves. If the potential of the primary current be too high, it will, when aided by the back elcctro motive force of the coil, cause vicious sparking at the contacts, and, on the other hand, if the voltage of the charging-current be very much reduced (to two volts, for instance) to 5 get rid of the sparking at the contacts then the current to be passed must be large and it becomes difficult to obtain suliicient conductivity at the make-and-break piece. The best practice, therefore, is to work at some point between these extreme limits, and it has been found that a potential of from four to eight volts is proper if a suitable make-andbreak piece is used. The present improvements comprise likewise a novel construction of the make-and-break mechanism which is able to pass a large current without undue heating at the potential mentioned-that is, four to eight voltsand which at the same time is able to disrupt such current quickly and without destructive sparking at the contact portions of the apparatus.

My invention may be embodied as shown in the accompanying drawings.

Figure l is a side elevation, and Fig. 2 an end elevation, of a contact-breaker constructed according thereto. Fig. 3 is a detail, and Fig. 4 a diagram, of circuits. Fig. 5 is a detail.

In the figures, M is a magnet mounted on a base-piece F, of slate, having a piece of felt f cemented to its bottom to cushion the apparatus. The magnet M is mounted with its poles uppermost. Above the poles is the armature A, supported from a spring at K. The spring K is preferably made up of several flat strips of phosphor-bronze or steel riveted together at points not subject to much bending. An upright post P supports the spring K. An adjusting-screw A is provided, having a head I, which slides between the spring K and a stationary piece L to vary the effective length of the spring K. The outer end of the armature A carries a rod R, threaded to receive weights IV. By changing the number of these weights and the spring adjustment at I any period of oscillation of the armature within the capacity of the apparatus may be had.

In Fig. 2, G is a vessel, of glass, resting on felt and containing an insulating liquid, such as water or alcohol, in which the contents are immersed. P I are posts which serve to carry the main current to two arms 0 0, (see also Fig. 3,) pivoted at p p to a hard-rubber cap Q for the vessel G. These arms 0 O are slotted at their outer ends, so as to embrace a threaded narrowed portion at the top of the posts P P and may then be clamped in position firmly by the thumb-nuts N N. The

pivots p p are at the ends of rods 4' 0", which extend down into the liquid and bear at their lower' threaded ends an insulating spacing piece .9, clamped between the nuts t i and the removable contact-points t i. A central rod 9 between the rods 1' and 0' has at its lower end a loose disk D, which may revolve freely on the rod 1' and move a short distance longitudinally thereon between the nuts 25 i The top of the rod r has a wooden or hardrubber plug to receive the blow of the rheotome hammer or armature. A spring K the lower end of which engages with the piece 8 and the upper end with a shoulder on 0- nor mally forces the disk D against the contactstuds 25 t, thus completing the circuit between the posts P P and through the primary winding of an induction-coil. E E are bindingscrews for the terminals of a suitable eondenser which is in shunt around the makeand-break. K Fig. 1, is the contact-spring for the magnet M, serving to maintain the armature in oscillation when current is applied.

Fig. 4 shows the preferred arrangement of circuits for the apparatus just described. In this figure, H are the lines from a current source of suitable potential, such as cells of storage battery or a small dynamo or motorgenerator of four to eight volts potential. Z is a switch between the dynamo and the apparatus. Current flows in two paths, one by the line a, post P arm 0, rod 7'', stud t, disk D, the other stud 25, red r, arm 0, post I and through the conductor 02 to the primary of the induction-coil in use, thence by line on and m, the other circuit being by conductor m to the binding-post B to the magnet M, from which, having traversed its winding, it is led by the contact-spring K to the other binding-post B and back to the line 977..

It will be noticed that current is flowing through the primary of the induction-coil except for the interval during which the armature A has in its attracted position struck the disk D away from the contact-studs t, and this being the case it is evident that the contact is closed for a much longer period than it is open. This gives ample time for the current to magnetize the core of the inductioncoil. Further, the apparatus makes two breaks in series with each other bet-ween the disk D and contact-studs t, and these parts being submerged in an insulating and cooling fluid there are practically no metallic vapors to form a conducting-path between the contact parts when they are being separated. The disk D being, as already stated, free to revolve around its support, there is continually being presented a new surface to the contact-studs, which again prevents arcing and heating or pitting of the metal. It is advantageous after running awhile to reverse the direction of current through the vessel G, so as to bring about an even wasting of the studs t by electrolytic action. These studs '4 and the disk D are very cheap and easily replaced, and wear at these points is not expensive.

To still further diminish this expense the modification shown in Fig. 5 may be employed, in which the rods 0" r are of stout copper wire held in clamps 0 0 so that they may be adjusted for wear, the clamps being connected in any suitable way (not illustrated) with the binding-posts oi the apparatus.

\Vhat Iclaim as new, and desire to secure by Letters Patent of the United States, is

1. Acontact device for induction-coils,comprising a pair of fixed terminals, a bridge nor mally held in contact with the fixed terminals by a spring, and a rheotom e-ha1nm er for opening the contacts.

2. In a contact device for induction-coils, the combination of a pair of fixed terminals with a bridge consisting of a rotatable disk normally closing the circuit.

3. In a contact device for induction-coils, the combination of a pair of fixed terminals, with a rod carrying a loosely-mounted disk forming a bridge, a spring normally closing the contacts, and a rheotome-hammer acting upon the rod to momentarily open them.

4. In a contact device for induction-coils, the combination of a number of contacts with a cooperating bridge forming a plurality of circuit-breaks in series, a spring normally holding the contacts together, and a rheotomehammer separating them.

5. In a contact device for induction-coils, the combination of a pair of rods forming circuit-terminals extending within a vessel c011- taining insulating fiuid, with a third rod exposed between the other two earryin g a loosely-mounted disk forming a bridging-contact for the terminals, with a spring for holding the disk normally in contact so as to close the circuit, and a rheotome-hammer momentarily opening the circuit, so that the time of closure is normally much longer than the time of opening.

In witness whereof I have hereunto set my hand this 1st day of April, 1897.

IIERMANN LEMP.

Witnesses:

JOHN W. GIBBONEY, ELII-IU THOMSON. 

